1. Field of the Invention
The present invention relates to a steel alloy for pipes, sheet metal or sections for manufacturing body reinforcements for motor vehicles, particularly side impact beams or A- and B-column reinforcements. The present invention also relates to a side impact beam or A- and B-column reinforcements manufactured from the steel alloy.
2. Description of the Related Art
Body reinforcements serve for the passive passenger protection in motor vehicles. They are subjected to high stresses particularly in the case of side impact crashes and front impact crashes. Accordingly, it is desired that components such as side impact beams or A- and B-column reinforcements have a high deformation capability for energy dissipation and absorption. This can be achieved by the mechanical characteristics of the material of the structural components. Normally, the strength and toughness required of the structural component are adjusted by the thermal treatment which follows the manufacture. can be achieved by the mechanical characteristics of the material of the structural components. Normally, the strength and toughness required of the structural component are adjusted by the thermal treatment which follows the manufacture.
U.S. Pat. No. 4,406,713 discloses a steel of high strength and toughness, preferably for manufacturing wires or rods, wherein the steel contains 0.05 to 0.3% carbon, 0.3 to 2.5% manganese, up to 1.5% silicon and at least one carbide former and nitrite former from the group of niobium, vanadium, titanium and zirconium. After austenitizing, this steel is quenched in such a way that it contains between 5 and 65% ferrite, and the remainder martensite.
When cold deforming such a martensite hardening steel which has an apparent yielding point of about 1,000 N/mm.sup.2, the deforming tools are subjected to high stresses and increased wear. This has a disadvantageous effect on the production costs, particularly in mass produced articles such as body reinforcements of motor vehicles